We've done WDW 40x's and never really paid alot of attention to morning early hour, but this last trip, January 2008, we were up and out earlier than usual and decided to take the boat to the MK. EMH was going on and it was quite crowded before the turnstiles but we waited and watched the train come in with the characters and saw all the glitz and glitter of opening, kinda cool and proceeded into the turnstiles, which wasn't all that bad. Once the other guests fanned out we ambled our way down Main Street to Adventureland and it seemed to be virtually empty. We had a grand time on the rides, even did Aladdin's Carpet and Jungle Cruise, just a walk on and POC was the same, rode POC 3 times and then headed to Frontierland and did most of the attractions all the way to the Haunted Mansion. Here's where we started to encounter the other guests and decided to make for Tomorrowland and head on out of the park. It wasn't as bad as I have read on here, rather nice so we opted to try HS EMH also, same thing, quite comfortable. I guess you never know until you give it a try, no guide service of magazine will know the true answer, they just guess for past years.
We always do evening EMH's, but we don't get there when they start but wait an hour, alot of people leave by then and the parks are just about empty, at least for our stay and the MK staying open till 1 am, most families are long gone. If you don't try it you'll never know and its your money. I read alot of stuff that isn't so, we just go and do our thing, if we encounter a huge crowd we skip to another park, that's whats good about hopper tickets.